Composite structure having modifier material printed thereon

ABSTRACT

A composite fiber may include at least one reinforcing filament formed of a first material. A second material maybe systematically deposited in a printed onto the at least one reinforcing filament such that at least one of a length, a width, and a thickness of the second material varies across a surface of the at least one reinforcing filament. The printed pattern may alter one or more properties of a composite structure containing the composite fiber.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a divisional application of and claimspriority to pending U.S. application Ser. No. 14/493,364 filed on Sep.23, 2014, and entitled PRINTING PATTERNS ONTO COMPOSITE LAMINATES, theentire contents of which is expressly incorporated by reference herein.

FIELD

The present disclosure relates generally to composite structures and,more particularly, to the printing of modifier materials onto compositelaminates.

BACKGROUND

Composite structures typically include continuous reinforcing fibersembedded in a resin matrix. A composite laminate is a type of compositestructure comprising a layup of composite plies arranged in a stack. Theindividual composite plies of a composite layup may be pre-impregnatedwith resin (e.g., prepreg plies) prior to stacking. The stack of prepregplies may be arranged such that the continuous reinforcing fibers ineach ply are oriented in a specific direction. Heat may be applied tothe stack to reduce the viscosity of the resin in each ply to allow theresin to intermingle with the resin of adjacent plies while the stack isconsolidated under pressure to remove voids and volatiles from withinthe composite layup. The resin may be cured or solidified into ahardened state and passively or actively cooled resulting in a compositestructure. Alternatively, instead of using prepreg plies, the compositeplies may be provided as dry fiber preforms arranged in a stack. Liquidresin may be infused into the stack while heat and/or pressure areapplied to consolidate and cure the resin after which the layup may bepassively or actively cooled to result in a composite structure.

The ability to tailor the direction of the reinforcing fibers in eachply of a composite layup results in a composite structure withsignificant performance advantages. Such performance advantages includea high specific strength and high specific modulus of elasticityrelative to the specific strength and modulus of metallic structures.Unfortunately, conventional composite laminates possess severalcharacteristics that may detract from their performance advantages. Forexample, conventional composite laminates may be susceptible toseparation at the resin-fiber interface due to the absence ofcrack-arresting features within the composite laminate. In addition, aconventional composite assembly may have relatively low mode IIinterlaminar shear strength or peel strength at the interface betweenco-bonded or co-cured composite laminates that make up the compositeassembly.

A conventional composite laminate may also possess relatively lowelectrical conductivity which may present challenges in transporting anddistributing electrical current through a composite structure such as inthe event of a lightning strike. In addition, composite laminates thatinterface with metallic components may be susceptible to corrosion as aresult of oxidation or reduction reactions that may occur between thecomposite laminate and metallic material. Furthermore, conventional dryfiber composite plies may lack sufficient tack to enable the dry fiberplies to stick together to allow for controlled stacking of the dryfiber plies into a preform.

Attempts to resolve the issue of separation at the resin-fiber interfaceof conventional composite laminates include randomly distributingthermoplastic material in bulk throughout a composite layup. Althoughthe random distribution of thermoplastic material may improve the modeII interlaminar strength, the lack of control at the resin-fiberinterface in conventional composite laminates results in low mode Iinterlaminar strength which may present challenges in preventing crackpropagation within fiber tows. Attempts to address low mode IIinterlaminar shear strength at the interface between composite laminatesof a conventional composite assembly include the addition of toughenersin the resin. Unfortunately, resin tougheners may have a relatively highmolecular weight that may undesirably increase the viscosity of theresin which may inhibit resin flow during infusion of fiber preforms.Attempts to address the issue of low electrical conductivity inconventional composite laminates include the addition of metallic meshesor foils across the surface of composite plies. Unfortunately, theaddition of separate metallic meshes or foils increases the cost,complexity, and production time of a composite structure.

Attempts to prevent corrosion at the interface between a compositelaminate and a metallic part include adding a separate layer offiberglass at the interface to act as a barrier ply against corrosion.Unfortunately, the addition of fiberglass increases the cost andcomplexity of manufacturing a composite laminate. The problem of lowtack in conventional dry fiber composite plies has been addressed byadding epoxy binders or nylons in the resin, or by using soldering ironsto locally heat and tack composite plies together. Unfortunately, epoxybinders or nylons have finite properties that limit the range oftemperatures and pressures required to form a ply stack of dry fiberpreforms. The local tacking together of composite plies using solderingirons is a time-consuming process that adds to the production time of acomposite structure.

As can be seen, there exists a need in the art for a composite laminateand manufacturing method that provides performance improvements such asimproved crack-resistance, improved interlaminar shear strength,increased electrical conductivity and corrosion resistance, and improvedtack in a broad range of temperatures.

SUMMARY

The above-noted needs associated with composite laminates arespecifically addressed by the present disclosure which provides acomposite fiber that may include at least one reinforcing filamentformed of a first material. A second material may be systematicallydeposited in a printed pattern onto the reinforcing filament such that alength, a width, and/or a thickness of the second material varies acrossa surface of the reinforcing filament. The printed pattern may have theeffect of altering one or more properties of a composite structurecontaining the composite fiber.

In a further embodiment, disclosed is a composite structure which mayinclude a resin and a plurality of reinforcing filaments embedded in theresin. The reinforcing filaments may be formed of a first material. Thecomposite structure may include a second material which may besystematically deposited onto the reinforcing filaments such that alength, a width, and/or a thickness of the second material varies acrossthe surface of the reinforcing filaments.

Also disclosed is a method of producing a composite fiber. The methodmay include providing a plurality of reinforcing filaments formed of afirst material. The method may additionally include printing a secondmaterial onto the plurality of reinforcing filaments using a depositionhead of a printer or printing device.

The features, functions and advantages that have been discussed can beachieved independently in various embodiments of the present disclosureor may be combined in yet other embodiments, further details of whichcan be seen with reference to the following description and drawingsbelow.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features of the present disclosure will become moreapparent upon reference to the drawings wherein like numbers refer tolike parts throughout and wherein:

FIG. 1 is a block diagram of a composite structure incorporating one ormore materials printed onto the reinforcing fibers formed of a firstmaterial and which may be configured as fiber tows, unidirectional tape,and/or woven fabric;

FIG. 2 is a perspective view of a composite layup including a stack ofunidirectional plies upon which one or more materials may be printed toimprove the properties of the composite structure;

FIG. 3 is a top view of a portion of a length of a unidirectional tapetaken along line 3 of FIG. 2 and illustrating a printed pattern of asecond material (and/or a third material, a fourth material, etc.)printed onto the unidirectional tape in the form of an array of dots toimprove the tack of the unidirectional ply;

FIG. 4 is a top view of a portion of a length of a unidirectional tapeshowing an example of a second material printed onto the unidirectionaltape in the form of perpendicular lines oriented transverse to alengthwise direction of the unidirectional tape and facilitatinganisotropic conductivity in the composite structure and/or tofacilitating crack termination in the composite structure;

FIG. 5 is a top view of a portion of a length of a unidirectional tapeshowing an example of a second material printed onto the unidirectionaltape in the form of cross-hatch patterns to facilitate crack arrestingin the composite structure;

FIG. 6 is a top view of a portion of a length of a unidirectional tapeshowing an example of a second material (and/or a third material, afourth, material, etc.) printed onto the unidirectional tape in the formof a combination of curves;

FIG. 7 is a perspective view of a portion of a length of a reinforcingfilament of a fiber tow and illustrating a sizing (e.g., a surfacecoating) that may be optionally included with the reinforcing filament;

FIG. 8 is a cross-sectional view of a unidirectional tape taken alongline 8 of FIG. 3 and showing an example of the distribution of a secondmaterial printed onto a top surface of the unidirectional tape;

FIG. 9 is a cross-sectional view of a unidirectional tape showing anexample of the distribution of a second material printed onto the topsurface and the bottom surface of the unidirectional tape;

FIG. 10 is a cross-sectional view of a unidirectional tape showing anexample of a second material of a printed pattern directly contactingboth of the adjacent composite plies of a composite structure;

FIG. 11 is a cross-sectional view of the composite layup illustrating apair of adjacent composite plies of unidirectional tape having the samefiber orientation and showing an example of contact between the printedpattern of second material on each one of the composite plies;

FIG. 12 is a cross-sectional view of a unidirectional tape of adjacentcomposite plies and showing a printed pattern of second materialdirectly contacting on one composite ply and mechanically engaging theprinted pattern of second material on an adjacent composite ply;

FIG. 13 is a cross-sectional view of a portion of a composite layupillustrating several adjacent composite plies of unidirectional tapehaving different fiber orientations and showing a second materialdirectly contacting the adjacent composite plies and further showing asecond material deposited between the sides of adjacent unidirectionaltapes;

FIG. 14 is a schematic illustration of an example of a system forprinting a printed pattern of second material onto a fiber tow;

FIG. 14A is a schematic illustration of print media taken along line 14Aof FIG. 14 and showing the print media made up of particulates;

FIG. 14B is a schematic illustration of the print media made up offilament strands;

FIG. 14C is an enlarged view of a tip of the deposition head taken alongline 14C of FIG. 14 and showing pixels being formed on a fiber tow;

FIG. 15 is a schematic illustration of an example of a robotic devicefor automated printing of a printed pattern of second material onto acomposite layup;

FIG. 16 is a schematic illustration of an example of a system forprinting a printed pattern of second material onto a woven fabric orunidirectional tape;

FIG. 17 is a schematic illustration of an example of a robotic devicefor automated printing of a printed pattern of second material onto awoven fabric, and/or unidirectional tape

FIG. 18 is a flowchart illustrating one or more operations that may beincluded in a method of applying a printed pattern of second materialonto a fiber tow, woven fabric, and/or unidirectional tape;

FIG. 19 is a flowchart illustrating one or more operations that may beincluded in a method of printing a printed pattern using a system shownin FIGS. 14-17;

FIG. 20 is a flowchart illustrating one or more operations that may beincluded in a method of printing a printed pattern onto one or morecomposite plies during layup on a preform tool.

DETAILED DESCRIPTION

Referring now to the drawings wherein the showings are for purposes ofillustrating various embodiments of the disclosure, shown in FIG. 1 is ablock diagram of a composite structure 100. The composite structure 100may be formed as a composite layup 102 or composite laminate 104including a plurality of composite plies 106. The composite plies 106may include reinforcing fibers 114 embedded within resin 112. Thereinforcing fibers 114 may be made up of a plurality of reinforcingfilaments 116. In some examples, the reinforcing filaments 116 mayinclude a sizing 138 (see, e.g., FIG. 7) or protective coating which maybe applied to the filament surface 118 of the reinforcing filaments 116during manufacturing of the reinforcing filaments 116. The sizing 138may be a surface finish that may be deposited in a uniform ornon-uniform sizing thickness 140 (FIG. 7) onto the reinforcing surfacealong the length of the reinforcing filament 116. The sizing 138 mayimprove the adhesion between the reinforcing filaments 116 and the resin112 and/or may protect the reinforcing filaments 116 from breakageduring processing such as during weaving and/or prepregging operations.The reinforcing filaments 116 may be formed of a first material 120 suchas carbon material or non-carbon material.

Advantageously, in the present disclosure, one or more modifiermaterials (e.g., a second material, a third material, a fourth material,etc.) may be applied to one or more reinforcing filaments 116, fibertows 114, unidirectional tapes 132 (FIG. 2), unidirectional sheet, wovenfabric 134 (FIG. 16), braided fabric, non-crimp fabrics, composite pliesor preforms, or any one of a variety of other fiber forms, as a means toalter the properties of the composite structure 100. The modifiermaterial or second material 202 (FIG. 4) or any number of othermaterials (a second material, a third material, a fourth material, etc.)may be systematically deposited in a predetermined printed pattern 200along a length or width of a reinforcing filament, fiber tow 114,unidirectional tape 132, unidirectional sheet, woven fabric 134,composite ply 106, or other fiber form such that at least one of alength 204, a width 206, and a thickness 208 of the second material 202varies across a surface of the reinforcing filament, fiber tow 114,unidirectional tape 132, unidirectional sheet, woven fabric 134, orother fiber form.

In some examples, the second material 202 may be applied to fiber forms(e.g., tows, tape, fabric) containing reinforcing filaments 116 (FIG. 2)that lack sizing 138. In other examples, the second material 202 may beapplied over the sizing 138 of the reinforcing filaments 116, fiber tows114, tape, woven fabric 134 (FIG. 16), or other fiber forms. The printedmodifier material or second material 202 may be different than the firstmaterial 120 of the reinforcing filaments 116. The second material 202(e.g., the modifier material) may be systematically deposited (e.g.,three-dimensionally printed) in a precisely-controlled printed pattern200 along a length and/or width of one or more reinforcing filaments116, fiber tows 114 (FIG. 2), unidirectional tape 132, woven fabric 134,or other fiber forms of a composite layup 102 to alter the properties ofa composite structure 100. The second material 202 may be printed asprint media 264 (FIG. 14A) in the form of inks, granules, particulates266, filament strands 268, and extrusion media.

The second material 202 may be applicable to or printed by othermanufacturing techniques including, but not limited to, handapplication/printing, spray coating, fused deposition molding,lithography, stereolithography, flexography, dry transfer, lasersintering, selective heat sintering, plaster-based 3D printing,layer-by-layer deposition, inkjet printing, chemical/thermal binding andextrusion to position. The second material 202 (FIG. 4) may include oneor more of organic monomers, prepolymers, polymers, metallic powders,inorganic fillers, and an aqueous or solvent-based solution. The secondmaterial 202 may also include fillers or secondary phases such asnano-silica, block copolymers, graphene platelets, carbon nanotubes, andother types of material. Advantageously, the printed pattern 200 may beprovided in a hierarchical structure within the composite laminate 104(FIG. 2) to achieve specific functionality or performance improvementsin the composite structure 100.

In one example, a second material 202 may contain polymer nanoparticles(not shown) that provide at least one of increased toughness, increasedflammability resistance, increased electrical conductivity, reducedcure-shrinkage-related distortion, reduced heat-of-reaction-relateddistortion, and/or reduced heat-of-reaction-related resin degradation.The polymer nanoparticles may be made from the same materials as theresin or at least one of thermoplastic material, acrylics,fluorocarbons, polyamides, polyolefins, polyesters, polycarbonates,polyurethanes, polyaryletherketones, polyetherimides, thermosettingmaterial, polyurethanes, phenolics, polyimides, sulphonated polymer(polyphenylene sulphide), a conductive polymer (e.g., polyaniline),benzoxazines, bismaleimides, cyanate esthers, polyesters, epoxies, andsilsesquioxanes. The polymer nanoparticles may also have at least one ofthe following properties: be at least partially soluble, have acore-sheath configuration, have a nanoparticle cure shrinkage less thanthe resin cure shrinkage, a nanoparticle CTE different than the resinCTE, a nanoparticle heat of reaction lower than the resin heat ofreaction, a greater distortion capability than the resin, release eithera catalyst or a hardener during a resin curing process, and the catalystor hardener may alter a reaction rate of the resin 112.

Any number of modifier materials (e.g., a second material 202, a thirdmaterial 212, a fourth material. etc.) may be printed onto any one of avariety of the above-mentioned fiber forms (e.g., filaments, fiber tows,tape, and/or woven fabric, etc.) in a highly-controlled manner. Forexample, a second material 202 (FIG. 4) may be printed on the nano-scaleto meso-scale (e.g., 10⁻⁹ mm to 10⁻³ mm) onto one or more fibers 114forms as a precisely-defined structural and/or functional modifier oradditive for a fiber-reinforced composite laminate structure. Printingof the second material 202 allows for a relatively high degree ofpositional accuracy and hierarchical control of the print media 264(e.g., the second material 202). In some examples, the second material202 may be printed such that the length 204, the width 206 (FIG. 4),and/or the thickness 208 of the second material 202 is within the rangeof approximately 0.01 to 100 microns. Advantageously, the length 204,the width 206, and the thickness 208 of the second material 202 may becontrolled in a highly precise manner to provide the desiredfunctionality improvements to specific locations of a compositestructure 100 (FIG. 1). For example, the deposition (e.g., the printing)of the second material 202 may improve the crack-resistance,interlaminar shear strength, electrical conductivity, and/or corrosionresistance of a composite structure, and/or the second material 202 mayincrease the tack of the composite plies 106 in a composite layup 102,as described in greater detail below.

FIG. 2 shows an example of a composite structure 100 formed as alaminated stack of unidirectional plies 110. Each one of theunidirectional plies 110 may include a plurality of parallel fiber tows114 laid side-by-side. In the example shown, the fibers 114 in onecomposite ply 106 may be oriented non-parallel to the fibers 114 in anadjacent composite ply 106 (e.g., above or below) in the stack. However,one or more of the composite plies 106 may include fibers 114 that areoriented parallel to the fibers 114 in an adjacent composite ply 106. Asindicated above, the reinforcing filaments 116 or fibers 114 may beformed of a first material 120. In one example, the first material 120(FIG. 1) may be carbon or graphite. However, in other examples, thereinforcing filaments 116 or fibers 114 may be formed of non-carbonmaterial. For example, the fibers 114 may be formed of boron, glass,ceramic, metallic material, and/or any other type of fiber material.

The fibers 114 in each one of the unidirectional plies 110 may beprovided as parallel fibers 114 of unidirectional tape 132 orunidirectional sheet (not shown). Each one of the composite plies 106(FIG. 2) may include a plurality of continuous fiber tows 114. A singlefiber tow 114 may include a bundle of several thousand reinforcingfilaments 116 (e.g., 1000 to 100,000 or more reinforcing filaments)bundled together. In some examples, a reinforcing filament may have afilament cross-sectional width or diameter of 5-30 microns. For example,a carbon reinforcing filament may have a filament cross-sectional widthof approximately 5-7 microns. Glass reinforcing filaments may have afilament cross-sectional width of 10-25 microns. Although not shown,composite fibers 114 in the present disclosure may also encompasschopped fibers 114 as may be incorporated into a fiber mat. In thisregard, composite fibers 114 of the present disclosure may also beprovided in any one of a variety of other fiber configurations, and arenot limited to the fiber configurations disclosed herein. In the presentdisclosure, the terms reinforcing filament, fiber, fiber tow, andcomposite fiber may be used interchangeably.

In some examples, a composite structure 100 may be formed of compositeplies 106 that may be pre-impregnated with resin 112 (e.g., prepregcomposite plies) which may be formed of prepreg fiber tows 114 (FIG. 2),prepreg unidirectional tape 132, and other forms of prepreg.Alternatively, a composite structure 100 may be formed as a dry fiberpreform 136. For example, a composite structure 100 (FIG. 2) may beformed by laying up dry composite plies 106, fiber tows 114, dryunidirectional tape 132 (FIG. 4), dry fiber sheets, dry woven cloth,fabric, and/or other forms of dry fiber. The dry fiber forms may bearranged in a stack of composite plies 106 onto which the secondmaterial 202 may be printed after which resin 112 may be infused in awet layup process.

In any one of the examples disclosed herein, the resin 112 and/or thereinforcing filaments 116 may be formed from thermoplastic material orthermosetting material. Thermoplastic material may include at least oneof the following: acrylics, fluorocarbons, polyamides, polyethylenes,polyesters, polypropylenes, polycarbonates, polyurethanes, polyaryletherketones, polyetheretherketone, polyetherketoneketone, andpolyetherimides. Thermoset material may include one of the following:polyurethanes, phenolics, polyimides, bismaleimides, polyesters,epoxies, cyanate esters, polysolfones, and silsesquioxanes. In addition,in any one of the examples disclosed herein, the resin 112 (FIG. 2)and/or the reinforcing filaments 116 or fibers 114 (FIG. 2) may beformed from materials such as carbons, silicon carbide, and boron. Thereinforcing filaments 116 or fibers 114 may also be formed from glasssuch as E-glass (alumino-borosilicate glass), S-glass (alumino silicateglass), pure silica, borosilicate glass, optical glass, and other glasscompositions.

FIG. 3 is a top view of a portion of a length of a fiber tow 114 orunidirectional tape 132 having a printed pattern 200 in the form of anarray of dots 214 printed onto the fiber tow 114 or unidirectional tape132. As indicated above, the fiber tow 114 or unidirectional tape 132may be comprised of a bundle 122 of continuous reinforcing filaments116. The reinforcing filaments 116 may or may not include sizing 138(see, e.g., FIG. 7) covering the reinforcing filaments 116. The fibertows 114 or unidirectional tape 132 may be provided as dry fibers 114 orthe fiber tows 114 or unidirectional tape 132 may be provided asprepreg. The array of dots 214 may be formed of one or more modifiermaterials that may be different than the first material 120 from whichthe reinforcing filaments 116 are formed. For example, the array of dots214 may be formed of a second material 202 which may be different thanthe first material 120. Some of the dots 214 in an array of dots may beformed of a third material 212 which may be a different composition thanthe first material 120 and/or the second material 202. The thirdmaterial 212 may be printed in the same or different size (e.g., length,width, thickness) and in the same or different printed pattern than thesecond material 202. A fourth material (not shown), a fifth material(not shown), or any number of other materials may be printed to providedifferent functionality. For example, such additional functionalitiesthat may be provided by the different materials may include, but are notlimited to, improved crack resistance, improved interlaminar shearstrength, increased electrical conductivity and corrosion resistance,and improved tack in a broad range of temperatures. It should be notedthat any one of the second, third, fourth, and/or fifth or morematerials may provide any one of the above-noted functionalities. Inthis regard, any number of materials may be combined in any number ofways to provide any one or more of the above-noted functionalities.

The array of dots 214 or any one of a variety of other geometricconfigurations of one or more modifier materials may be arranged in aprinted pattern 200 (FIG. 3) to provide one or more of a variety ofdifferent functionalities. For example, a printed pattern 200 may beconfigured to provide improved tack to the composite plies 106. One ormore modifier materials may be provided in a printed pattern 200 thatmay provide chemical bonding between adjacent composite plies 106 (FIG.2) and/or mechanical and/or physical interlocking between adjacentcomposite plies 106. For example, a modifier material may be printed ona fiber form (e.g., a fiber tow, unidirectional tape, woven fabric) andmay bond with the reinforcing filaments 116 as the modifier material isapplied or printed onto the fiber form by a printer 260 (FIG. 14). Themodifier material may have a tackiness that allows the modifier materialto stick to an adjacent composite ply 106. In some examples, modifiermaterials may be printed with mechanical features formed on the printedpattern 200 such as teeth 224 (not shown) or notches that may beengageable to the reinforcing filaments 116 (FIG. 3) of an adjacentcomposite ply 106. In a further embodiment, a printed pattern 200 on onecomposite ply 106 may be printed with mechanical features for engagingthe printed pattern 200 of an adjacent composite ply 106, as describedbelow.

Furthermore, modifier materials may be selected to be compatible withthe processing temperatures of the composite layup 102. For example,modifier materials may be selected to provide tack between compositeplies 106 (FIG. 2) within a range of temperatures from room temperatureto elevated temperatures associated with consolidation and curing of theresin 112 (FIG. 2). The improved tack may enable dry fiber compositeplies or prepreg plies to stick together to allow for controlledhandling and stacking of the composite fiber plies into a compositelayup 102 (FIG. 2). In this regard, the improved tack provided by theprinted pattern 200 may stabilize the composite plies 106 againstrelative movement during stacking, vacuum bagging, resin infusion,consolidation, and other composite processing operations.

Any one or more of a variety of printed patterns 200 may also providefunctionally in the form of improved ply bridging between adjacent pliesin a composite laminate 104 (FIG. 10). For example, a printed pattern200 (FIG. 10) of one or more modifier materials may provide crackprevention or crack-arresting features in the composite structure 100.For example, one or more modifier materials may improve the adhesivebond between the reinforcing filaments 116 and the resin 112 (FIG. 10).In addition, a printed pattern 200 of one or more modifier materials mayact as a toughening mechanism which may inhibit or prevent crackinitiation or crack growth within the composite structure 100. One ormore modifier materials may be printed onto the fiber tows 114 orunidirectional tape 132 in a precisely controlled length 204, width 206,and/or thickness 208 to bridge across the interlaminar region 108 (seee.g., FIGS. 10-13) between an adjacent pair of composite plies 106 asdescribed in greater detail below. The bridging of adjacent compositeplies 106 may distribute localized stress concentrations within thecomposite laminate 104 and thereby minimize and prevent crack initiationor crack growth within the composite laminate 104.

In some examples, the printing of a modifier material in the form of anarray of dots 214 or other geometric configuration may improve thetoughness of a composite laminate 104. For example, a printed pattern200 (FIG. 3) of modifier material may induce a controlled pullout,release, or detachment of modifier material particles from reinforcingfilaments 116 (FIG. 3) as a stress release mechanism to inhibit orprevent crack formation and/or crack growth. In another example, amodifier material may have a composition or mechanical properties thatallow for a controlled amount of deformation of the modifier materialwhen the composite laminate 104 (FIG. 2) is subjected to certain typesof loads (e.g., loads of a certain magnitude and/or direction).

In the present disclosure, a second material 202, a third material 212,and/or any number of other modifier materials may be systematicallyprinted onto a fiber form (e.g., fiber tows, unidirectional tape, wovenfabric, etc.) using a deposition head 262 (e.g., see FIGS. 14-17) of aprinter 260 such as a three-dimensional ink jet printer or other printerconfiguration. The process of applying one or more modifier materialsonto a fiber form may take advantage of the precision in size (e.g.,length, width, thickness) and position with which the printer depositionhead 262 may print pixels 210 (FIG. 14C) of modifier material in anadditive process to form a predetermined printed pattern 200 on a fiberform.

A deposition head 262 of a printer 260 may be configured to print thematerials (e.g., the second material 202, third material 212, etc.) inpixels 210 (FIG. 14C) of up to 100 microns in diameter and at athickness of up to 100 microns. In some examples, the size of each pixel210 may be between approximately 0.1 to 10 microns in diameter. In otherexamples, each one of pixels 210 may be applied to a fiber tow, tape, orfabric in a thickness of the each pixel of at least approximately 0.01microns. A succession of pixels 210 may be printed using a printer 260deposition head 262 (FIG. 14C) to build up a printed pattern 200 onto afiber tow 114 or other fiber form such that the final printed pattern200 (FIG. 13) has a precisely-controlled length 204, width 206, andthickness 208.

FIG. 4 shows a length of a unidirectional tape 132 having a secondmaterial 202 printed in a printed pattern 200 of perpendicular lines 216oriented transverse to a lengthwise direction of the unidirectional tape132. The printed pattern 200 of perpendicular lines 216 may facilitateanisotropic electrical conductivity along a direction parallel to theperpendicular lines 216 of the printed pattern 200. The arrangement ofperpendicular lines 216 may facilitate the transportation and/ordistribution of electrical charge through a composite structure 100 suchas in the event of a lightning strike on an aircraft. The printedpattern 200 of perpendicular lines 216 may also facilitate cracktermination or prevent crack propagation in the composite structure 100.For example, the perpendicular lines 216 may prevent propagation ofcracks that may form in the resin 112 between reinforcing filaments 116when a load is applied perpendicular to the lengthwise direction (e.g.,the load-carrying direction) of the reinforcing filaments 116.

FIG. 5 shows a length of a fiber tow 114 with a printed pattern 200 inthe form of cross-hatch patterns 218 along the length of the fiber tow114. Similar to the perpendicular lines 216 shown in FIG. 4, across-hatch pattern 218 may also facilitate crack termination or preventcrack propagation that may form and the resin 112 (FIG. 2) of acomposite structure 100. The cross-hatch patterns 218 may also provide apathway to assist in distributing electrical charge through a compositestructure 100. One or more of cross-hatch patterns 218 may be printedusing one or more of the modifier materials. For example, a cross-hatchpattern 218 may be formed of a second material 202 and a third material212 which may be different than the first material 120 from which thereinforcing filaments 116 may be formed. The second material 202 mayprovide one type of functionality such as providing a tougheningmechanism to prevent crack initiation or crack growth in the compositestructure 100 (FIG. 2) during thermal cycling and/or during certainloading conditions on the composite structure 100. The third material212 may provide another type of functionality to the composite structure100 such as improving the electrical conductivity of the compositestructure 100.

FIG. 6 shows a length of a unidirectional tape 132 with a printedpattern 200 in the form of a combination of curves 220. The curves 220may be formed of one or more modifier materials as indicated above. Inthis regard, the printed pattern 200 may vary in length and width toinclude a combination of a variety of sizes, shapes and configurations.For example, a printed pattern 200 may include any combination of dots214, lines 216 (FIG. 4), cross-hatches 218 (FIG. 5), and/or curves 220,or any one of a variety of other printed pattern 200 configurations.

In any example disclosed herein, any one or more modifier materials(e.g., a second material 202, a third material 212, etc.) may be printedonto a fiber form (e.g., reinforcing filaments, fiber tows,unidirectional tape, woven fabric, etc.) in any one of a variety ofdifferent printed patterns 200. A modifier material such as a secondmaterial 202 may be systematically deposited such that at least one of alength 204, a width 206 (FIG. 3), and a thickness 208 (FIG. 8) of thesecond material 202 varies across a surface of one or more filaments orone or more fibers 114. For example, a second material 202 may besystematically deposited in a printed pattern 200 along any portion of alength of a fiber tow 114, unidirectional tape 132, or woven fabric 134(FIG. 16). In some examples, a printed pattern 200 may be repeated alonga portion of a length of a fiber tow 114, unidirectional tape 132 (FIG.5), or woven fabric 134. In other examples, a printed pattern 200 may beprinted in a random spacing along the length of a fiber tow 114,unidirectional tape 132, or woven fabric 134.

As may be appreciated, any one or more of a variety of differentmodifier materials may be incorporated into the printed pattern 200(FIG. 6) to provide one or more desired functionalities for thecomposite structure 100 (FIG. 2). In this regard, the systematicdeposition of the modifier material onto a fiber form of a compositelaminate may result in a composite structure 100 that has at least onecomposite structure property that is altered relative to the propertiesof a composite structure having reinforcing filaments that are devoid ofthe modifier material. The altered composite structure property mayinclude toughness, volume fraction, permeability, modulus, cureshrinkage, heat of reaction, filament tack, flammability, and electricalconductivity, and other types of functionalities. In some examples, athird material 212 may be systematically deposited onto one or morereinforcing filaments 116 or other fiber forms using a deposition head262 (FIG. 14A) of a printer 260. The result of depositing a secondmaterial 202 and a third material 212 may be a composite structure 100that has at least two (2) different composite structure properties thatare altered relative to the properties of a composite structure havingreinforcing filaments that are devoid of the second and third material.

In an embodiment, one or more modifier materials may be applied orprinted onto a fiber form in one or more printed patterns 200 (FIG. 6)to improve the interlaminar shear strength and/or peel strength of thecomposite structure 100 (FIG. 2) at the interfaces between matingcomposite components (not shown). For example, a modifier material maybe applied to a fiber form in a printed pattern 200 to improve theinterlaminar shear strength and/or peel strength at an interface betweena composite skin and a composite stiffener of a resin-infused laminatestructure. In another example, one or more modifier materials may beprinted onto one or more of the fiber tows 114, unidirectional tapes 132(FIG. 6), and/or woven fabric 134 (FIG. 16) of a laminated compositestructure 100 in a manner to locally increase or decrease the fracturetoughness, elastic modulus, and/or or strain-to-failure of the compositestructure 100 in anticipation of predicted environmental and/ormechanical loading conditions to which the composite structure 100 maybe subjected during its service life.

In another example, one or more modifier materials may be applied to afiber form in a printed pattern 200 that functions as a corrosionbarrier between a laminated composite structure and a metallic part. Inthis regard, the printed pattern 200 (FIG. 6) may act as a corrosionbarrier against oxidative and/or a reduction reactions that may occurbetween a carbon fiber laminate and a metallic component such as analuminum component. In a further example, one or more modifier materialsmay be printed onto a fiber formed to improve the flammability, smoke,and/or toxicity characteristics of a composite structure 100 (FIG. 2).Advantageously, in any of the examples disclosed herein, modifiermaterials may be printed onto a fiber form to locally tailor theproperties of the composite laminate 104 (FIG. 2) in correspondence withthe anticipated service environment and/or loading conditions. Forexample, modifier materials may be printed in a manner to alter themodulus of elasticity at different locations within the compositelaminate 104 to accommodate the loading conditions of the compositelaminate 104. In this regard, by printing of one or more differenttypes, quantities, and geometric configurations of modifier materials onfiber tows, tapes, plies, and/or woven fabric in specific regions of alayup 102, the performance of a composite structure 100 may be tailoredto the anticipated service conditions and operating environment of thecomposite structure 100.

FIG. 7 shows a portion of a length of a reinforcing filament 116 of afiber tow 114 (FIG. 5) and illustrating a sizing 138 (e.g., a surfacecoating) that may be optionally included with the reinforcing filament116. As indicated above, the sizing 138 may be applied duringmanufacturing of a reinforcing filament 116. The sizing 138 may protectthe reinforcing filament 116 from damage such as breakage duringmanufacturing and/or during later processing such as during weavingand/or layup of composite plies 106.

FIG. 8 shows a cross section of a fiber tow 114 and/or unidirectionaltape 132 formed of the plurality of reinforcing filaments 116 of a firstmaterial 120. Also shown is a printed pattern 200 of modifier material(e.g., a second material 202) printed onto an outer portion of thebundle 122 of reinforcing filaments 116. The modifier material is shownprinted on a top surface 128 of the fiber tow 114 and/or unidirectionaltape 132. As indicated above, the modifier material may be printed in adesired thickness 208. For example, modifier material may be printed ina thickness 208 of up to 100 microns of greater.

FIG. 9 shows a cross section of a fiber tow 114 and/or unidirectionaltape 132 formed of a plurality or bundle 122 of reinforcing filaments116. A modifier material (e.g., a second material 202) may be printed ina printed pattern 200 on at least two (2) different planes 124associated with the bundle 122 of reinforcing filaments 116. Forexample, a printed pattern 200 may be applied to both a top surface 128and a bottom surface 130 of the unidirectional tape 132. The modifiermaterial may be printed in a distributed pattern and at a desiredthickness 208 to enable ply bridging with composite plies 106 adjacentto the top surface 128 and bottom surface 130. In addition, a printedpattern may be applied to one or more sides of unidirectional tape (seee.g., FIG. 13).

FIG. 10 is a cross-sectional view of a composite layup 102 (FIG. 2)showing a printed pattern 200 bonding together the unidirectional tape132 of adjacent composite plies 106 of a composite structure 100. Theprinted pattern 200 of modifier material may be applied to thereinforcing filaments 116 of one or both of the composite plies 106 at adepth that enables mechanical interlocking and/or chemical interactionof the composite plies 106. In FIG. 10, the printed pattern 200 ofmodifier material directly contacts and may provide improved tack withor may adhesively bond with both of the composite plies 106. Althoughthe unidirectional plies 110 in FIG. 10 have the same fiber orientation,the modifier material may directly bond adjacent composite plies 106having different fiber orientations. In one example, a printed pattern200 may vary in length, width, and height to include any combination ofgeometric features (not shown) for mechanical interlocking of pliesincluding, but not limited to, ball and sockets, hooks and loops,dovetail wedges and grooves, curved peaks and troughs, bionicinterlocking features, irregular three-dimensional shapes, and any othertype of geometric feature.

FIG. 11 is a cross-sectional view of a composite layup 102 (FIG. 2)including a pair of adjacent composite plies 106 of unidirectional tape132. Modifier material may be printed onto each one of the compositeplies 106. The modifier material of one composite ply 106 may be incontact with the modifier material of the adjacent composite ply 106.The modifier materials may be mechanically and/or chemically interlockedwith one another. In any of the examples disclosed herein, thecomposition of modifier materials may be selected such that contactbetween the modifier materials result in an interface with miscible orimmiscible interaction between the modifier materials.

Furthermore, any one or more modifier materials may be soluble,partially soluble, or insoluble in the resin 112 (FIG. 2). A soluble orpartially soluble modifier material may be configured to releasecatalyst or hardener during curing of the resin to locally alter thecure properties (e.g., cure time and/or cure temperature) of the resin.In this regard, a modifier material may at least partially dissolve inthe resin when the soluble material reaches a predetermined temperaturecausing the modifier material to progressively release catalyst orhardener into the resin, and thereby reduce the resin cure time relativeto the cure time of resin lacking the modifier material. In addition,any one or more modifier materials may have a heat of reaction that islower than the resin heat of reaction which may have the effect oflocally reducing the cure temperature to thereby reduce local thermaldistortion in the composite laminate as a result of differences in thecoefficient of thermal expansion (CTE) of the resin relative to the CTEof the fibers 114. In a further example, any one or more modifiermaterials may be porous to locally increase the strain capability of theresin along at least one direction when the composite structure issubjected to an external load or force.

FIG. 12 is a cross-sectional view of a composite layup 102 (FIG. 2)wherein a modifier material may be printed on each one of the compositeplies 106 to facilitate interlocking of the modifier material of eachcomposite ply 106. The printed pattern 200 of modifier material on eachone of the composite plies 106 may be printed with mechanicalinterlocking features 222. For example, the printed pattern 200 on oneof the composite plies 106 may include teeth 224, hooks, or othermechanical features for physically engaging and interlocking withcorresponding mechanical interlocking features 222 that may be printedon the modifier material of the opposing composite ply 106. In someexamples, the modifier material of one composite ply 106 in FIG. 12 maybe configured to chemically interlock with the modifier material of theadjacent composite ply 106.

FIG. 13 is a cross-sectional view of a composite layup 102 (FIG. 2)showing several adjacent composite plies 106 of unidirectional tape 132having different fiber orientations. Printed patterns 200 of modifiermaterial may be printed on the composite plies 106 to facilitate orenable improved tack and/or ply bridging between the adjacent compositeplies 106. A printed pattern 200 may also be applied between the sidesurfaces 131 of adjacent unidirectional tapes 132. In any one of theexamples disclosed herein, modifier materials may be printed onto one ormore fiber forms to provide any number of desired functionalities forthe composite laminate 104. For example, modifier materials may beprinted to improve the tack, electrical conductivity, corrosionresistance, interlaminar shear strength and fracture toughness,crack-arresting capability, thermal properties, and otherfunctionalities. Advantageously, the ability to precisely control thematerial, size, geometry, and position of each printed pattern 200 withmicro-scale accuracy in a repeatable manner may result in an improvementof the specific performance of composite laminates.

FIG. 14 is a schematic illustration of an example of a system forprinting a printed pattern 200 of second material 202 onto a fiber tow114 or unidirectional tape 132 or form. In the example shown, the systemincludes a bobbin 282 of fiber tow 114. The fiber tow 114 (FIG. 13) maybe dry fiber or the fiber tow 114 may be pre-impregnated with resin 112(FIG. 2). The fiber tow 114 may be fed via feed rollers 270 into aprinter bed 256. The printer bed 256 may include a printer 260 having adeposition head 262 for printing modifier material in a printed pattern200 onto the fiber tow 114. In some examples, the printer 260 may bemovable along a guide track 258 along a left-to-right direction relativeto the plane the paper as may be desirable for a pulse-printingoperation wherein a length of the fiber tow 114 may be moved into theprinter bed 256 and stopped to allow the printer 260 to apply theprinted pattern 200 onto the length of fiber tow 114. The printer 260may also be movable in a direction in and out of the plane of paperwhile the tow is stationary within the printer bed 256. In otherexamples, the printer 260 may be stationary and the fiber tow 114 may becontinuously movable through the printer bed 256 while the printer 260continuously prints the printed pattern 200 onto the fiber tow 114.

In FIG. 14, the printer 260 may operate in response to acomputer-readable print program 254 instructions (e.g., code) based on adigital model 252 of the printed pattern 200. In some examples, thedigital model 252 of the printed pattern 200 may be based on acomputer-aided-design (CAD) model of the printed pattern 200 which maybe generated on a computer 250 and which is shown displayed on thescreen of the computer 250. The print program 254 may provide positionalcontrol of the deposition head 262 and may also control the size, shape,and general configuration of the printed pattern 200 that may be printedusing print media 264 (e.g., the modifier material). In some examples,the printer bed 256 may include a display 274 for observation of theprogress of printing the printed pattern 200 on a fiber tow 114 (FIG.13). After printing the printed pattern on a fiber tow 114, the printedfiber tow 276 may be wound on a bobbin 282. Although not shown, thebobbin 282 of printed fiber tow 276 may be transported to a compositelayup area wherein the fiber tow 114 may be laid up into a compositelaminate 104 in a manually layup process and/or by using an automatedtape laying machine (not shown).

FIG. 14A is a schematic illustration of an example of print media 264made up of particulates 266. The particulates 266 may be provided in agenerally spherical shape. However other shapes are contemplated. FIG.14B is a schematic illustration of print media 264 made up of filamentstrands 268. As indicated above, the print media 264 (e.g., the modifiermaterial) may include organic monomers, pre-polymers, polymers metallicpowders, inorganic fillers, and other modifier materials. FIG. 14C is anenlarged view of a tip of the deposition head 262 showing pixels 210being formed on a fiber tow 114. As mentioned above, each pixel 210 mayhave a diameter of up to 100 microns or larger and may have a thickness208 of at least approximately 0.1 microns. The deposition head 262 mayprint a succession of pixels 210 in order to build up a printed pattern200 of desired thickness 208, length 204, width 206, and geometry.

FIG. 15 is a schematic illustration of an example of a robotic device272 for printing a printed pattern 200 of modifier material onto a fiberform. In the example shown, the robotic device 272 may includearticulated arms for positioning the deposition head 262 of the printer260 relative to a composite laminate 104 of unidirectional tape 132(FIG. 13). The robotic device 272 may control the printer 260 to print apredetermined printed pattern 200 of modifier material on successivecomposite plies 106 in a stack of a composite laminate 104. The roboticdevice 272 may be operated in response to computer-readable printprogram 254 instructions (e.g., code) based on a digital model 252 ofthe printed pattern 200, similar to the arrangement described for theprinter bed 256 of FIG. 14.

FIG. 16 is a schematic illustration of an example of a printer bed 256for printing a printed pattern 200 of modifier material onto a wovenfabric 134 or unidirectional tape 132 or sheet. In the example shown,the system includes a roll 284 of woven fabric 134 which may be dryfabric or prepreg fabric. The woven fabric 134 may be continuously fedvia feed rollers 270 into a printer bed 256 having a printer 260 with adeposition head 262 for printing modifier material in a printed pattern200 onto the woven fabric 134. The printer 260 may be stationary or theprinter 260 may be movable in any one of a variety of differentdirections relative to the printer bed 256 similar to theabove-described arrangement of FIG. 14. After printing the printedpattern 200 onto the woven fabric 134, the printed fiber tow 278 may bewound onto a roll 286.

The system of FIG. 16 may optionally be operated in a pulse modearrangement wherein a section or length of the woven fabric 134 may bemoved into the printer 260 head and the printer 260 may be moved whiledepositing a printed pattern 200 on the length of woven fabric 134,after which the printed woven fabric 278 may be wound on a roll 286. Anew length of the woven fabric 134 may be fed into the printer bed 256for printing. The fiber tow 114 printing system illustrated in FIG. 14may also be operated in a pulse mode arrangement.

FIG. 17 shows an example of a robotic device 272 for automated printingof a printed pattern 200 of modifier material onto a woven fabric 134and/or unidirectional tape 132 (FIG. 16) or sheet. The robotic device272 may be operated in a manner similar to that described above for FIG.16. In this regard, the print program 254 may cause a robotic device 272to position the printer 260 relative to the composite layup 102 whilethe deposition head 262 is controlled to print the predetermined printedpattern 200.

FIG. 18 is a flowchart illustrating one or more operations that may beincluded in a method 300 of applying a pattern of second material 202(FIG. 4) onto a fiber tow 114 (FIG. 4), woven fabric 134 (FIG. 16),and/or unidirectional tape 132 (FIG. 4). Step 302 of the method 300 mayinclude providing a plurality of reinforcing filaments 116 (FIG. 4)formed of a first material 120. As indicated above, the plurality ofreinforcing filaments 116 may be provided as fiber tows, unidirectionaltape, woven fabric, or other fiber forms.

Step 304 of the method 300 may include printing a second material 202onto the plurality of reinforcing filaments 116 using a deposition head262 of a printer 260. For example, FIGS. 14 and 16 illustrate a systemincluding a printer 260 of a printer bed 256 for positioning thedeposition head 262 relative to the fiber form. FIGS. 15 and 17illustrate a robotic device 272 having articulated arms for positioningthe deposition head 262 of a printer 260 relative to a compositelaminate 104. In some examples, the deposition head 262 may be moved orpositioned based on programmable code of a print program 254 that may bederived from a digital model 252 (computer-aided-design model) of apredetermined printed pattern 200 generator on a computer 250.

As may be appreciated, alternative systems may be implemented forprinting a modifier material onto a fiber form. The printing of themodifier material may occur during fabrication of one or more forms areinforcing filament 116 (FIG. 8) such as during fabrication of fibertows 114 (FIG. 8), unidirectional tape 132 (FIG. 9), woven fabric 134,and/or fiber preforms 136. The printing of the modifier material may beperformed by moving a printer deposition head 262 relative to a fiberpreform 136 (FIG. 2) containing the plurality of reinforcing filaments116 and/or by printing the second material 202 (FIG. 13) onto the fiberperform during layup of the fiber preform 136.

In some examples, the printed pattern 200 may be formed of a modifiermaterial that has a length 204, a width 206, and/or a thickness 208 ofapproximately 0.01 to 500 microns. In some examples, the second material202 may be printed in a predetermined printed pattern 200 on an outerportion 126 of the plurality of reinforcing filaments 116. For example,FIGS. 8-13 illustrate a printed pattern 200 deposited onto a top surface128 and/or a bottom surface 130 of fiber tows 114, unidirectional tape132. As indicated above, the modifier material (e.g., print media) maybe provided in any one of a variety of different sizes, shapes,materials, and configurations, including, but not limited to,particulates 266 and/or filament strands 268 as respectively shown inFIGS. 14A and 14B.

In one example, the printing of the second material 202 (FIG. 1) mayinclude the targeted placement of the second material 202 in resin-richpockets (not shown) at divots and/or intersections of the fiber tows ofwoven fabric or between plies and/or tapes. In one embodiment, duringthe process of laying up composite plies of a woven fabric or prepreg,polymer nanoparticles (not shown) may be placed into the resin-richpockets such as at the divots and/or intersections of the fiber tows ofthe woven fabric to prevent microcracking or stress cracking resultingfrom changes in temperature of the composite structure 100.

FIG. 19 is a flowchart illustrating one or more operations that may beincluded in a method 400 of printing a printed pattern 200 onto a fiberform using one of the systems schematically illustrated in FIG. 14-17.Step 402 of the method may include providing the fiber form to beprinted such as fiber tow 114, woven fabric 134, or unidirectional tape132. Step 404 may include loading the fiber tow 114 onto a bobbin, orloading woven fabric 134 or unidirectional tape 132 on a roll. Step 406may include transferring the fiber tow 114 or woven fabric 134 to aprinter bed 256 as shown in FIGS. 14 and 16, or positioning a printer260 of a robotic device 272 over the fiber tow 114, unidirectional tape132, or woven fabric 134 as shown in FIGS. 15 and 17.

Step 408 of the method 400 may include providing print media 264 forprinting onto the fiber tow 114, woven fabric 134, or unidirectionaltape 132. Step 410 may include loading the print media 264 into aprinter 260 as shown in FIGS. 14-17. Step 412 may include designing aprinted pattern 200 to be printed onto a fiber form. For example, acomputer 250 may be used to create a digital model 252 of a printedpattern 200. Step 416 may include creating a numerical control (N/C)three-dimensional print program 254 (e.g. code) based on the digitalmodel 252. The print program 254 may include instructions regarding thelength, width, height, and/or geometry with which the modifier materialis to be printed onto the fiber form.

Step 418 may include running the print program 254 to operate a printerof a printer bed 256 (FIGS. 14 and 16) or a robotic device 272 (FIGS. 15and 17). Step 420 may include printing the printed pattern 200 onto thefiber tow 114, woven fabric 134, or unidirectional tape 132. Asindicated above, the fiber form may be passed through the fiber bed on acontinuous basis or on a pulse basis while the deposition head 262prints the printed pattern 200 onto the fiber form. Alternatively, thefiber form may be stationary as shown in FIGS. 15 and 17, and therobotic device 272 may move the deposition head 262 to print the printedpattern 200 onto a composite laminate 104. Step 422 may include loadingthe printed fiber tow/tape or printed woven fabric 134 onto a respectivebobbin 282 or roll 286.

The method may include transporting the bobbin 282 or roll 286 to alayup area (not shown) and laying up the printed fiber form into acomposite laminate 104. The printed fiber form may include prepregfibers containing the printed pattern 200 (FIG. 14) and arranged in astack. Heat may be applied to the stack to reduce the viscosity of theprepreg resin causing the resin of adjacent composite plies 106 (FIG.13) to intermingle. The resin may be allowed to cure and/or harden intoa solidified state after which the resin may be passively or activelycooled to form the composite structure 100. Alternatively, the printedfiber form may be dry fibers containing the printed pattern 200 andwhich may be arranged in a stack. Liquid resin may be infused into thestack and heat and/or pressure may be applied to consolidate and cureand/or harden into a solidified state after which the resin 112 (FIG. 2)may be passively or actively cooled to form the composite structure 100.

FIG. 20 is a flowchart illustrating one or more operations that may beincluded in a method 500 of printing one or more printed patterns 200onto one or more composite plies 106 during layup on a preform tool (notshown). Step 502 of the method may include providing print media 264 anda print program 254 to one or more robotic devices 272 in a mannersimilar to that described with regard to FIG. 19. For example, the printmedia 264 may be loaded into the deposition head 262 of a robotic device272 similar to the robotic device 272 shown in FIG. 17. A printedpattern 200 may be designed such as by using a computer aided designprogram to create a digital model 252 (FIG. 17) of the printed pattern200 which may be transformed into a numerical control (N/C)three-dimensional print program 254 (e.g. code) and loaded into therobotic device 272.

Step 504 of the method 500 may include providing a preform tool (notshown) upon which one or more composite plies 106 may be laid up. Forexample, prepreg or dry fiber composite plies 106 may be precut to theapproximate shape of a final composite structure 100 to be manufactured.One or more of the composite plies 106 may be laid up onto the preformtool during Step 506 of the method 500.

Step 508 of the method 500 may include activating the robotic device 272to cause the deposition head 262 to print the printed pattern 200 ontothe composite ply 106. As indicated above, the deposition head 262 maybe configured to apply or print any number of different materials in anynumber of different patterns 200 onto any portion of a composite ply106. For example, a second material may be printed onto the compositeply 106 to provide a specific functionality such as increased toughnessfor improved crack resistance in the final composite structure. A thirdmaterial, fourth material, and any number of additional materials may beprinted onto a composite ply 106 in any number of printed patterns 200to provide specific functionalities such as improved interlaminar shearstrength, increased electrical conductivity and corrosion resistance,improved tack in a broad range of temperatures, or any number of otherfunctionalities, without limitation.

After completing the printing onto a composite ply 106, one or moreadditional composite plies 106 may be laid up over a previously-printedcomposite ply 106, and the deposition head 262 of the robotic device 272may print another printed pattern 200 onto the newly-laid composite ply106. Step 510 of the method may include repeating the layup Step 506 andthe printing Step 508 until the desired number of composite plies 106have been laid up and/or printed. Advantageously, the above-methodallows for a high degree of precision and flexibility in applyingprinted patterns 200 to specific regions of a composite layup 102 usingany number of different types of printed media or material (e.g., asecond material, a third material, etc.).

Illustrative embodiments of the disclosure may be described in thecontext of a method (not shown) of manufacturing and/or servicing anaircraft, spacecraft, satellite, or other aerospace component.Pre-production, component manufacturing, and/or servicing may includespecification and design of aerospace components and materialprocurement. During production, component and subassembly manufacturing,and system integration of aerospace components takes place. Thereafter,the aircraft, spacecraft, satellite, or other aerospace component may gothrough certification and delivery in order to be placed in service.

In one example, aerospace components produced by the manufacturing andservicing method may include an airframe with a plurality of systems andan interior. Examples of the plurality of systems may include one ormore of a propulsion system, an electrical system, a hydraulic system,and an environmental system. Any number of other systems may beincluded. Although an aerospace example is shown, different illustrativeembodiments may be applied to other industries, such as the automotiveindustry.

Apparatuses and methods embodied herein may be employed during at leastone of the stages of an aerospace component manufacturing and/orservicing method. In particular, a composite structure 100 (e.g., FIG.1), a coating, an injection-molded plastic, and/or an adhesive may bemanufactured during any one of the stages of the aerospace componentmanufacturing and servicing method. For example, without limitation, acomposite structure may be manufactured during at least one of componentand subassembly manufacturing, system integration, routine maintenanceand service, or some other stage of aircraft manufacturing andservicing. Still further, a composite structure may be used in one ormore structures of aerospace components. For example, a compositestructure may be included in a structure of an airframe, an interior, orsome other part of an aircraft, spacecraft, satellite, or otheraerospace component.

Additional modifications and improvements of the present disclosure maybe apparent to those of ordinary skill in the art. Thus, the particularcombination of parts described and illustrated herein is intended torepresent only certain embodiments of the present disclosure and is notintended to serve as limitations of alternative embodiments or deviceswithin the spirit and scope of the disclosure.

What is claimed is:
 1. A composite fiber, comprising: at least onereinforcing filament formed of a first material and a second materialsystematically deposited in a pattern onto the at least one reinforcingfilament such that at least one of a length, a width, and a thickness ofthe second material varies across a surface of the at least onereinforcing filament.
 2. The composite fiber of claim 1, wherein: thereinforcing filament includes a sizing applied in a uniform sizingthickness to a filament surface of the at least one reinforcingfilament; and the second material systematically deposited onto thesizing of the at least one reinforcing filament.
 3. The composite fiberof claim 1, wherein: at least one of the length, the width, and thethickness of the second material is approximately 0.01 to 100 microns.4. The composite fiber of claim 1, wherein: the second material iscomprised of any one or more of the following: inks, granules, extrusionmedia, organic monomers, prepolymers, polymers, metallic powders,inorganic fillers in an aqueous or solvent-based solution, silica, blockcopolymers, graphene platelets, polymer nanoparticles, and carbonnanotubes.
 5. The composite fiber of claim 1, wherein: the secondmaterial is applied onto the at least one reinforcing filament using adeposition head of a printing device.
 6. The composite fiber of claim 1,further comprising: one or more additional materials including a thirdmaterial systematically deposited onto the at least one reinforcingfilament.
 7. The composite fiber of claim 1, wherein: the secondmaterial is applied to at least two different surfaces associated with abundle of reinforcing filaments forming the composite fiber.
 8. Thecomposite fiber of claim 7, wherein: the surfaces include at least oneof a top surface, a bottom surface, and side surfaces of the compositefiber.
 9. The composite fiber of claim 1, wherein: the second materialis printed onto at least one reinforcing filament as pixels each havinga thickness of up to 100 microns.
 10. The composite fiber of claim 1,wherein: the at least one reinforcing filament comprises a plurality ofreinforcing filaments in at least one of the following forms: a fibertow, unidirectional tape, woven fabric, non-crimp fabric, a braid, acomposite ply or preform.
 11. A composite structure, comprising: aresin; a plurality of reinforcing filaments embedded in the resin andformed of a first material; and a second material systematicallydeposited onto the plurality of reinforcing filaments such that at leastone of a length, a width, or a thickness varies across a filamentsurface of the plurality of reinforcing filaments.
 12. The compositestructure of claim 11, wherein: the composite structure has at least onecomposite structure property that is altered due to systematicdeposition of the second material onto the reinforcing filamentsrelative to the composite structure property of a composite structurehaving reinforcing filaments that are devoid of the second material. 13.The composite structure of claim 12, wherein: the altered compositestructure property includes at least one of the following: toughness,volume fraction, permeability, modulus, cure shrinkage, filament tack,flammability, and electrical conductivity.
 14. The composite structureof claim 12, further comprising: one or more additional materialsincluding a third material systematically deposited onto the at leastone reinforcing filament using a deposition head of a printer; and thecomposite structure having at least two different composite structureproperties that are altered due to printing of the respective second andthird material to the at least one reinforcing filament relative to thecomposite structure properties of a composite structure havingreinforcing filaments that are devoid of the second and third material.15. The composite structure of claim 12, wherein: the plurality ofreinforcing filaments each include a sizing applied in a uniform sizingthickness to a filament surface of the plurality of reinforcingfilaments; and the second material systematically deposited onto thesizing of the plurality of reinforcing filaments.
 16. The compositestructure of claim 12, wherein: at least one of the length, the width,and the thickness of the second material is approximately 0.01 to 100microns.
 17. The composite structure of claim 12, wherein: the secondmaterial is comprised of any one or more of the following: inks,granules, extrusion media, organic monomers, prepolymers, polymers,metallic powders, inorganic fillers in an aqueous or solvent-basedsolution, silica, block copolymers, graphene platelets, polymernanoparticles, and carbon nanotubes.
 18. The composite structure ofclaim 12, wherein: the second material is applied onto the plurality ofreinforcing filaments using a deposition head of a printing device. 19.The composite structure of claim 12, wherein: the second material isprinted onto the plurality of reinforcing filaments as pixels eachhaving a thickness of up to 100 microns.
 20. The composite structure ofclaim 12, wherein: the plurality of reinforcing filaments are providedin at least one of the following forms: fiber tows, unidirectional tape,woven fabric, non-crimp fabric, a braid, a composite ply or preform.